Looks like another "Ash Hole" sale pitch to me. Usually when a combustion air vent is added, it is because there is a negative pressure issue within the dwelling. This negative pressure competes with the natural draft fireplace. If this intake is connected directly to the basement, it will more than likely vent to the basement area and not up as intended. The basement is known to have the greatest negative pressures in the dwelling. Sometimes it is all about sales. I wonder what the cost of this addition was.

__________________
Dale W. Feb, Professional Education For Professional Results
Training: F.I.R.E. Service (805) 552-9958 www.gotoFIRE.com
Inspection/Investigation: F.I.R.E. Associates (805) 552-9954 www.FireAssociates.org